The invention relates to a device for releasable fastening of tube or pipe ends, said device having shell parts connected pivotably together and having flanges directed radially inwards on the shell parts, to retain tube or pipe ends. Such a device may have a toggle lever lock, through which two adjacent shell parts may be connected together, and which has a toggle lever and a spring connected jointly to the latter and its toggle lever engages one end of the first of two shell parts in a pivotable manner.
In such a device, it is known to allow the spring to engage with its end relatively close to the pivot axis of the toggle lever, while the spring itself engages over the point of engagement between the two adjacent shell parts and is connected to a part remote from the end of the other shell part, this fastening takes place usually by hooking the appropriately bent end of the spring into a slit in this shell part. When the toggle lever is open, the spring may be unhooked so that the shell may be unfolded. When closing the toggle lever, the pivot axis formed between the toggle lever and spring is pivoted over into its closed position via that pivot axis with which the toggle lever is held pivotably against the shell part assigned to it. In this closed position, it rests on the shell part last mentioned. In order that the toggle lever is able to reach this position over dead centre, the spring must be capable of expansion.
In particular, because of the required expansibility of the spring, the contact pressure which may be achieved with the flanges of the shell parts cannot have very large values. If a tube under very high pressure is to be fastened with the device, the sealing effect to be achieved by the flanges may, in some cases, be insufficient; in other words the loadability of the device is not sufficiently high.
Furthermore, the spring must have a curve bent in a particular manner in order that the required expansibility is ensured. However, this curve in turn demands a fairly large rigidity of the spring. As a result manufacture is more expensive.
Another disadvantage of the known embodiment may be seen by the fact that the spring is exposed with respect to the otherwise enclosed shape of the shell parts and forms an unprotected region within which foreign bodies and dirt may penetrate into the inside of the device.